B型套筒角焊缝力学性能模拟实验

X80钢管道的环焊缝缺陷一般采用B型套筒补强的方法。为了进行B型套筒角焊缝力学性能模拟实验，并探究超声冲击对其力学性能的影响，设计多组X80钢材质的品字形角焊缝试件，用以模拟补强管道的拉伸、弯曲、低周疲劳工况。采用万能实验机和疲劳实验机，测得超声冲击处理前后试件的最大拉伸力、最大弯曲载荷和拉伸力-循环次数曲线。实验结果表明，超声冲击处理角焊缝，对B型套筒结构的抗拉强度、弯曲强度、疲劳强度基本没有影响；在管道环焊缝完全开裂的极端情况下，B型套筒角焊缝能承受的极限弯矩约为管道母材的69%。实验结果可为确定B型套筒的适用条件提供基础数据。

Simulation Test of Mechanical Properties of B-type Sleeve Fillet Weld

The girth weld defects of X80 steel pipes are generally reinforced by B-type sleeves. In order to carry out the simulation test of the mechanical properties of the B-type sleeve fillet welds, and explore the influence of ultrasonic impact on the mechanical properties, a number of sets of X80 steel fractal fillet weld specimens are designed to simulate the tensile and bending of the reinforced pipe, and low-cycle fatigue conditions. Using universal testing machine and fatigue testing machine, the maximum tensile force, maximum bending load and tensile force-cycle number curve (analog S-N curve) of the specimen before and after ultrasonic impact treatment are measured. The test results show that ultrasonic impact treatment of fillet welds has basically no effect on the tensile strength, bending strength, and fatigue strength of the B-type sleeve structure; in the extreme case of complete cracking of the pipe girth weld, the ultimate bending moment that the B-type sleeve fillet weld can withstand is about 69% of the pipe base material. The test results can provide basic data for determining the applicable conditions of the B-type sleeve.